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Patented Oct. 6, 1925.

UNITED STATES PATENT} oFFicE.

'WILHELM nna znmefqr 131113.12In wunmiaisnoar, am) osmium norm, or BERLIN- rnnr'row, GERMANY; nssrenon 'ro Aca'nm GESELLSGHAFT ronsmmn rszamv xenon, or nnnmmonnmsnx.

rnooass m umuiacrunmo DYES.

No Drawing.

O V l N02 containing in the 2-position-an OH-group and by ring closure. By the employment of an acidreducing a cut the ring closure occurs -durin the re uction; otherwise it is effected su s'equently by acidification.

The new dyes furnish on wool green chrom lakes of an excellent fastness to the action of light. If a 2-h droxy-3 (2'-nitrophenylmercapto) -1 .4-nap ployed as starting materia which contains in the benzene or in the naphthalene nucleus a sulphonic acid group water-soluble dyes are obtained. -Water-insoluble dyes manufactured be sulphonated.

The2 hydroxy-3- (2-nitrophenylmercapto)-1. 1-naphthoquinone and its derivatives are obtainable by causing a 2-9. lamino-' or 2-acidylamino e 3 --chloro-1.4-nap thoquinone or a sulphonic acid thereof to react with 2-nitroth1ophenol or a derivative thereof and heating the products with strong alkali so as to exchange the substituted amino group for hydroxyl. 2-hydroxy-3(2'-nitrophenylmercapto)'-1.4-naphthoquinone is a bright orange red crystalline powder which meltsat 245 C. and dissolves in concentrated sul huric acid and in alkalies-to an orange ye low solution. Addition of an excess of sodium hydroxide precipitates .from the solution a sodium salt of brassy lustre.

ffiedp The liquid solidifies,

{in the process described may Application filed December 12,'18%4. Serial No. {155,551.

Treatment with feebly fuming sulphuric "acid in the cold converts the naphthoqui none into an orange yellow sulphonic acid easily soluble in water. o

The following examples illustratejthe invention, the parts being by weight:

Example 1.33 parts of 2 hydroxy-3- (2'- nitrophenylmercapto) 1A;- naphthoquinone are dissolved by means of 13' parts of sodium hydroxide solution of 40 B. specific gravity in 100 parts of cold water and the K solution is mixed with about 7 parts of hydrosulphiteuntil it is decolorized. -Air is now vpassed through the liquid until it has become dark brown, whereupon it is acidiarticularly easily when warmed, to a thick violet magma of the dye. The latter is a crystalline violet owder, soluble in concentrated sulphuric am to a brown violet solution. In dilute alkali metal hydroxide solution it dissolves temporarily to a greenish blue solution from which the sparingly soluble dark blue alkali metal salt separates. 1

The formula of the dye produced by the foregoing example is i tho uinone is em- .thiophenol by condensation in the manner described above and decomposed when heated to about 255 C.) there is obtained a dye which diwolves in concentrated sulphuric acid to a green solution, which on dilution With form of steel blue needles which are filtered.

By dissolving them in hot water and aciditying the greenish blue solution thus obtained the free sulphonic acid is obtained in the form of ared violet crystalline powder Which dissolves to a blue red solution in hot Water. The atterchromed dyeing on Wool is blue green.

Ewamplefd-By substituting for the parent material of Example 4 the very similar 2-hydroxy-3- (2-nitrophenylmercapto) 1.4 7 naphthoquinone 6- (7) sulphonic acid (obtainable from Q-phenylamino-3-chloro- 1.4 naphthoquinone 6 (7) sulphonic acid,

Journal fiir Praktisch'e Chemie, vol. 37 ,l page 190) there is obtained a dye which dissolves in Water ,to a violet solution and in alkalies to a blue green solution; its after-chromed dyeings on Wool are yellow green.

What We claim ls,- A process for manufacturing dyes of the general formula:

by treating with reducing agents eoznpounds of the general formula:

In testimony whereof W8 affix our signatures.

WILHELM HERJZBERG GERHARD HQPPE; 

